Numerical Dispersion Error Reduction in EM-Calculations for Accelerators

In this contribution two recently proposed numerical schemes with no dispersion along the beam axis for the simulation of ultra-short, relativistic bunches are investigated. This property is of particular interest in the computation of electromagnetic wakes in linear accelerators. The numerical results obtained by both schemes are bench-marked against the analytical solution for an electron bunch moving within a cylindrical pipe with perfectly conducting walls. As a more realistic application, the longitudinal wake potential of a single bunch passing through several cells of the TESLA-FEL.